Roll paper printers and other types of printing devices that hold a roll of continuous recording paper in a roll paper holder, and print to the recording paper pulled from the paper roll are known from the literature. Due to limited space where the printing device is used, for example, some printing devices of this type are configured so that they can be used in either of two orientations, vertically or horizontally. For example, the roll paper printer (printing device) described in PTL 1 can be placed in a horizontal orientation on a horizontal surface, or mounted vertically on a wall. When mounted on a wall, the surface that is the back when placed horizontally is on the bottom facing down. PTL 2 describes a facsimile machine (printing device) that can used either vertically or horizontally.
The locations of the parts of the printing device and the operating direction relative to the user change depending on the orientation (placement) of a printing device that can be used vertically or horizontally. The locations of the parts of the printing device and the operating direction also change relative to the vertical axis. This can adversely affect ease of use. Where the paper roll is held inside the printing device and the conveyance path may also change, resulting in problems with supplying the recording paper and detecting the recording paper. To accommodate the location where the paper roll is held changing, the roll paper printer described in PTL 1 has recesses for holding the roll paper at two locations in the roll paper holder. The printer also has two locations for installing a detector for detecting the roll paper, and the location of the detector can be changed according to the orientation of the printer. Because the orientation of the display unit reverses relative to the user when the orientation of the facsimile machine changes, the facsimile machine described in PTL 2 enables control reversing the orientation of the content displayed on the display unit, or reversing the orientation in which the display unit is installed.